We consider two-dimensional Fermi liquids in the vicinity of a quantum transition to a phase
with commensurate, antiferromagnetic long-range order. Depending upon the Fermi-surface …

Motivated by the recent report of broken time-reversal symmetry and zero momentum
magnetic scattering in underdoped cuprates, we investigate under which circumstances …

The angle-resolved photoemission (ARPES) technique has been developed rapidly over the
last decade, accompanied by the improvement of energy and momentum resolutions. This …

We investigate whether the staggered-flux phase (SFP) is realized in slightly doped phases
of the Cu-O high-T c superconductors. Using a mean-field solution of the tJ model, we …

It is shown that the usual three-center cation-anion-cation model or fourth-order pertrubation
expression (in the Cu-O hopping parameter tpd) does not give a useful (even qualitative) …

Three types (three-band, two-band, and one-band) of effective Hamiltonians for HgBa 2 CuO
4 and three-band effective Hamiltonian for La 2 CuO 4 are derived by improving the …

Recent angle-resolved photoemission (ARPES) results for the insulating cuprate Sr 2 CuO 2
Cl 2 have provided experimental data that can be directly compared to the (theoretically) …

We investigate the nature of the superconducting state of high-T c materials from a
microscopic theory and from a phenomenological analysis of experimental data. The …

We derive at-J model with electron-phonon coupling from the three-band model, considering
modulation of both hopping and Coulomb integrals by phonons. While the modulation of the …

We consider a two-dimensional Fermi-liquid coupled to low-energy commensurate spin
fluctuations. At small coupling, the hole Fermi surface is large and centered around Q=(π, π) …